/Engine/Plugins/FX/Niagara/Source/Niagara/Public/NiagaraComponent.h
Sets the desired age of the System instance and designates that this change is a seek. When seeking to a desired age the The component can optionally prevent rendering.
[UFUNCTION](Programming/UnrealArchitecture/Reference/Functions)(BlueprintCallable, Category=Niagara, Meta=(DisplayName="Seek to Desired Age")) void SeekToDesiredAge ( float InDesiredAge )